Affiliation: 1] State Key Laboratory of Chem/Bio-Sensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha, 410082, P. R. China [2] School of Chemistry, The University of Manchester, Oxford Road, Greater Manchester, M13 9PL, United Kingdom.

ABSTRACTFlexible energy storage devices are highly demanded for various applications. Carbon cloth (CC) woven by carbon fibers (CFs) is typically used as electrode or current collector for flexible devices. The low surface area of CC and the presence of big gaps (ca. micro-size) between individual CFs lead to poor performance. Herein, we interconnect individual CFs through the in-situ exfoliated graphene with high surface area by the electrochemical intercalation method. The interconnected CFs are used as both current collector and electrode materials for flexible supercapacitors, in which the in-situ exfoliated graphene act as active materials and conductive "binders". The in-situ electrochemical intercalation technique ensures the low contact resistance between electrode (graphene) and current collector (carbon cloth) with enhanced conductivity. The as-prepared electrode materials show significantly improved performance for flexible supercapacitors.

Mentions:
Based on the SEM observation, graphene was successfully exfoliated and acted as interlinkers to interconnect individual carbon fibers. It is well-known that graphene always has high surface area, therefore, it is expected that the interconnected carbon fibers by graphene, that is, Ex-CC would show much higher surface area than pristine CC. We performed the Brunauer Emmett Teller (BET) testing for Ex-CC as well as CC for comparison. Figure 2 showed the nitrogen adsorption-desorption isotherms of CC and Ex-CC. As can be seen, CC gave type I isotherms characterized by a plateau that is nearly horizontal to the P/P0 axis, indicating the microporous nature of of carbon fibers in CC19. For Ex-CC, the type IV isotherm with pronounced adsorption at low and medium relative pressures indicate the existence of a large number of mesopores and micropores created by the as-exfoliated graphene in Ex-CC. The hysteresis loop in the isotherms of Ex-CC indicates the Ex-CC is porous. The total pore volume of Ex-CC is 0.424 cm3/g, much higher than that of CC (0.011 cm3/g). After the electrochemical cation intercalation, Ex-CC exhibited much higher surface area (68.5 m2/g) than CC without intercalation (11.5 m2/g). The enhancement of the surface area by the in-situ interconnected graphene could be clearly found.

Mentions:
Based on the SEM observation, graphene was successfully exfoliated and acted as interlinkers to interconnect individual carbon fibers. It is well-known that graphene always has high surface area, therefore, it is expected that the interconnected carbon fibers by graphene, that is, Ex-CC would show much higher surface area than pristine CC. We performed the Brunauer Emmett Teller (BET) testing for Ex-CC as well as CC for comparison. Figure 2 showed the nitrogen adsorption-desorption isotherms of CC and Ex-CC. As can be seen, CC gave type I isotherms characterized by a plateau that is nearly horizontal to the P/P0 axis, indicating the microporous nature of of carbon fibers in CC19. For Ex-CC, the type IV isotherm with pronounced adsorption at low and medium relative pressures indicate the existence of a large number of mesopores and micropores created by the as-exfoliated graphene in Ex-CC. The hysteresis loop in the isotherms of Ex-CC indicates the Ex-CC is porous. The total pore volume of Ex-CC is 0.424 cm3/g, much higher than that of CC (0.011 cm3/g). After the electrochemical cation intercalation, Ex-CC exhibited much higher surface area (68.5 m2/g) than CC without intercalation (11.5 m2/g). The enhancement of the surface area by the in-situ interconnected graphene could be clearly found.

Bottom Line:
The low surface area of CC and the presence of big gaps (ca. micro-size) between individual CFs lead to poor performance.The in-situ electrochemical intercalation technique ensures the low contact resistance between electrode (graphene) and current collector (carbon cloth) with enhanced conductivity.The as-prepared electrode materials show significantly improved performance for flexible supercapacitors.

Affiliation:
1] State Key Laboratory of Chem/Bio-Sensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha, 410082, P. R. China [2] School of Chemistry, The University of Manchester, Oxford Road, Greater Manchester, M13 9PL, United Kingdom.

ABSTRACTFlexible energy storage devices are highly demanded for various applications. Carbon cloth (CC) woven by carbon fibers (CFs) is typically used as electrode or current collector for flexible devices. The low surface area of CC and the presence of big gaps (ca. micro-size) between individual CFs lead to poor performance. Herein, we interconnect individual CFs through the in-situ exfoliated graphene with high surface area by the electrochemical intercalation method. The interconnected CFs are used as both current collector and electrode materials for flexible supercapacitors, in which the in-situ exfoliated graphene act as active materials and conductive "binders". The in-situ electrochemical intercalation technique ensures the low contact resistance between electrode (graphene) and current collector (carbon cloth) with enhanced conductivity. The as-prepared electrode materials show significantly improved performance for flexible supercapacitors.